Endometriosis is a common gynecological disease that occurs one woman in ten. Endometriosis ovarian cyst (benign ovarian cyst, called also as “chocolate cyst”) is a kind of endometriosis and is a disease in which the endometriosis develop in the ovary and blood from the endometriosis accumulate to form a cyst.
It is reported that about 1% of the endometriosis ovarian cysts is cancerated into ovarian cancer (“endometriosis-associated ovarian cancer EAOC” which is a generic name of ovarian cancer that occurs from endometriosis). From epidemiological view point, if the cyst has a diameter of more than 6 cm and enlarges suddenly in a short period of time, extirpation is recommended for patients of 45 years old or older because of high risk of carcinogenesis.
However, it was reported a percentage of cases that are diagnosed as actual malignant tumor after surgery was only about 1%. In other words, a larger number of unnecessary invasive treatment were forced. Therefore, now, the likelihood of canceration is determined firstly by morphological evaluation of the cyst by using an ultrasonic diagnostic device or a nuclear magnetic resonance imaging (MRI).
Patent Document 1 discloses an ovarian cancer diagnose method by detecting overexpression of a specific biomarker that is selectively overexpressed in ovarian cancer.
Non-Patent Document 1 describes such a fact that the genetic factors that are believed to be involved in the development of endometriosis-associated ovarian cancer (“EAOC”) are mutation of PTEN gene and strong expression of HNF-1 b gene or the like, while, in case of the endometriosis ovarian cysts, the concentration of free iron in the cyst fluid (using a production amount of lipid peroxide as an indicator) and an oxidative stress marker value become significantly higher comparing to other benign ovarian cysts, and hence the Non-Patent Document 1 suggests that a likelihood of accumulation of DNA damage which is caused by oxidative stress related to the free iron in the endometriosis ovarian cyst fluid and which lead to carcinogenesis in epithelial cells of endometriosis.